EM78P417N/418N/419N
8-Bit Microprocessor with OTP ROM
6.12.2 Residual Voltage Protection
When the battery is replaced, device power (Vdd) is removed but residual voltage
remains. The residual voltage may trips below Vdd minimum, but not to zero. This
condition may cause a poor power on reset. Fig. 6-16 and Fig. 6-20 show how to
create a protection circuit against residual voltage.
VDD
VDD
33K
EM78P417/ 8/ 9N
Q1
10K
/RESET
100K
1N4684
Fig. 6-19 Residual Voltage Protection Circuit 1
VDD
VDD
R1
R2
EM78P417/ 8/ 9N
/RESET
Q1
R3
Fig. 6-20 Residual Voltage Protection Circuit 2
6.13 Code Option
EM78P417/8/9N has two CODE option words and one Customer ID word that are not a
part of the normal program memory.
Word 0
Word1
Word 2
Bit12 ~ Bit0
Bit12 ~ Bit0
Bit12 ~ Bit0
Product Specification (V1.0) 06.23.2005
• 61
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
